Secularism in India is a foundational constitutional norm, not a postscript to the Preamble

The word 'secular' means 'worldly'. Literally speaking, its domain contrasts with the spiritual or transcendental aspects of a person's life. However, the term "secular" does not mean anti-religious, nor does it imply irreligiosity. In no sense does it bear any animosity or grudge towards aspects of life that one considers religious or spiritual. Simply stated, the secular and the religious reflect two different spheres of life, with the possibility of intersection between them. A person's secular concerns relate to his material and earthly life, and include transient subjects such as career, finances, and social relations. They encompass practical knowledge, inter alia, of science, arts, and engineering.

In the realm of politics, that is, in the management of community affairs, or at the highest level where sovereignty predominantly inheres, in the affairs of the State—the term secular connotes keeping the spiritual–religious sphere (and their reciprocal influences) at an arm's length from the governance of the State. Whether these domains are separated by an impervious wall or an osmotic barrier depends on the nature of the polity envisaged in a State's constitutional law.

In modern times, the emergence and normative appeal of the secular state have been shaped by historical experience specifically, by the grave consequences that followed from the absence of secular governance. The principle of secularism has, in this sense, been sanctified through a baptism of blood, most vividly illustrated in the annals of medieval Europe and, closer to us in both time and space, in the partition of the Indian subcontinent. These experiences underscored the destructive potential of religiously inflected state power and reinforced the necessity of institutional separation between religion and the affairs of the state.

The long history of religious freedom

One of the most significant episodes that accelerated the intellectual momentum in favour of the secularisation of the state was the Thirty Years' War (1618–1648) in Central Europe, which resulted in the deaths of an estimated four to eight million people. The casus belli lay in struggles for control over parcels of Europe on the basis of the religious affiliations of the rulers, notably, between the Protestant and Catholic powers. This confessional logic of sovereignty continued to haunt Europe for generations, even after the Peace of Westphalia (1648) formally brought the conflict to an end.

It is not surprising that, at roughly the same historical moment, the anxieties of the age and the personal experiences of Roger Williams, a Puritan minister in the Massachusetts Bay Colony, led him to establish Providence Plantation as the first polity to erect a deliberate "wall of separation" between church and state. In this settlement, the government was restricted to only 'civil things' and the citizens declared their determination "still to hold forth liberty of conscience." The settlement, which later evolved into the colony of Rhode Island, became a refuge for those "distressed of conscience." This conception of institutional separation later informed Thomas Jefferson's articulation of the "wall of separation" and was subsequently reflected in the American constitutional tradition, serving as a powerful inspiration for secular constitutional models across the world.

However, the recognition of 'freedom of religion' in statecraft was not a modern invention. The phenomena, in different hues and colors, have existed for millennia. The first major empire in history, the Persian Empire, which stretched from Central Asia to the Mediterranean and encompassed a multitude of nationalities and faiths, ensured that local religions and cults were neither suppressed nor interfered with, but actively protected. The Cyrus Cylinder explicitly refers to the "rebuilding of temples" and the "restoration of cults" in Babylon, while the Bible recounts Cyrus the Great facilitating the repatriation of the Jews from Babylonian captivity. In such contexts, freedom of conscience emerged not only as a desirable ideal but also as a practical necessity for the governance of large and culturally diverse polities.

Millennia later, in the thirteenth century, the much-maligned Mongol Empire emphasized religious coexistence and freedom of belief, while also asserting the supremacy of the state over religion in the governance of public affairs. Möngke Khan, the fourth Khagan of the Mongol Empire, denounced the pernicious enmity among the religions of the world. In his view, the truth-claims of different faiths could not be reliably adjudicated; the only path to concord lay in guaranteeing religious freedom while placing all religions under the authority of the state.

One of the Enlightenment philosophers, John Locke, advanced a powerful rationale for the necessity of religious toleration. First, he argued that earthly judges, including the state, lack the capacity to reliably adjudicate the truth-claims of competing religions. Second, even if such discernment were possible, the enforcement of a single "true religion" would fail to achieve its intended purpose, since genuine belief cannot be produced through coercion or violence. Lastly, Locke argued that religious coercion would generate greater social disorder than accommodating religious diversity.

Spinoza, a contemporary of John Locke, was even more explicit and forceful in his advocacy of religious tolerance. He argued that the state should regulate only external actions, not the private beliefs of individuals, since beliefs in themselves do not harm the state. Spinoza maintained that freedom of thought, belief, and expression is essential both for public peace and for individual flourishing. Conversely, he insisted that religious authorities must never exercise civil power and must always remain subordinate to the sovereign to ensure public order. This line of reasoning exerted a profound influence on subsequent political philosophy and on modern constitutional frameworks, many of which have embraced religious toleration as a foundational principle.